After single mother Tereon Grant is stabbed to death in the middle of the night, all signs point to her ex-boyfriend being the killer; then, Detectives Quinn and Velazquez dig deeper into the case, uncovering a dark secret that changes everything.

When the skull of 11-year-old Alan Watson is found in a field, Quinn and Velazquez take the case of a murder that took place almost a decade before.

To trained eyes, it appears as though Shaquilla Weatherspoon's killers staged the crime scene to make it look like a robbery; knowing better, Detectives Quinn and Velazquez investigate those closest to Shaquilla to find the truth.

When U.S. Air Force veteran John Ray is found beaten and stabbed to death in his apartment, the crime scene looks like a random robbery.

New mother Sparkle Rai, 21, is found strangled to death by her boyfriend who instantly becomes the prime suspect; David Quinn and Vince Velazquez uncover a surprising new suspect from Rai's past.

Quinn and Velazquez are called when Jerry Heard is found dead from gunshot wounds. They learn Heard spends his nights at a local bar, and the night he was killed, he was flirting with two different women, one with an armed boyfriend. With at least three potential suspects, the detectives get to work.

Neighborhood character Willie Bell is found naked and dead early in the morning; with nothing else to go on, Quinn and Velazquez discover that Willie was seen with two different women the night before he was found.

Cassandra Bryant, 38, is found naked and barely clinging to life; she dies in the ambulance before identifying her attacker, leaving Quinn and Velazquez to find her killer.

When Detectives Quinn and Vince investigate the shooting of Antwan Curry, they find a trail of blood leading away from the murder scene; they set out to find the injured person, not knowing if they're looking for another victim or the killer.

Longtime partners Quinn and Velazquez are chosen to solve the case of Apriel Allen, a woman who was murdered in her apartment two years prior; the detectives begin with a clean slate and hope to bring some peace to Allen's loved ones.

After immigrant Mamadou Berry is murdered, Quinn and Velazquez seek to find his killer; the yearlong investigation pits the detectives against the International Robbin Crew, a ruthless and deadly Atlanta gang.

After a homeless man is shot and killed, Quinn and Velazquez assume it's a simple case; after reports come back matching the murder scene to other ongoing murder cases, the detectives realize they're on the trail of a serial killer.

Two assailants attempt to rob a man's house on a hot summer night; as events unfold, a simple robbery ends with the murder of a young couple.

When elderly Edward, who always pays his rent on time, fails to do so, the apartment manager calls in a welfare check. As it turns out, Edward has been tortured and murdered in his apartment.

Demetrius Robbins is a husband and father who always puts his family first, then the unthinkable happens; David Quinn and Vince Velazquez investigate, coming to the realization that Robbins has fallen victim to an unspeakably horrific crime.

Days pass and no one sees or hears from Jimmie Atkins; Atlanta police find Atkins murdered in his home; David Quinn and Vince Velazquez rush to the scene, only to discover a hard truth about the people who are dear to one's heart.

Ayesha Turner lives a quiet life in southwest Atlanta, then everything changes one evening; David Quinn and Vince Velazquez receive a missing person's report and begin trying to figure out what happened to Ayesha.

Carlton Benn is a great person who works for a disaster relief company, then his roommate calls police to report that Carlton is dead, and Vince and Quinn spring into action.

U.S. Navy veteran Eric Clark is a loving son, brother and husband who starts a bartending business to make some extra money; one night, Eric drives to Atlanta to pick up alcohol for an event, but this road trip will turn out to be his last.

Charles Smith is a bright young man with musical ambitions; one night, all his dreams come to an end when he is found nearly dead at a crossroads in Atlanta.

Hardworking Valerie Payton resorts to prostitution to give her son a better life, then Valerie attracts a man does the unthinkable.

Mark Schaller was new to Atlanta. While out one night, Mark began chatting with someone at a bar. Chatting quickly became something more, unfortunately it was something no one could have dreamt of.

Returning home in the early morning hours, Jerrick Jackson and his fiancé meet several assailants in their driveway, and shots are fired killing Jerrick.

Darius Bottoms, 18, leaves his friend's apartment after a fun-filled night of video games; Darius notices two figures standing near his car as he starts to drive away, then he is ambushed and shot dead.

On Sept. 13, 2010, Vince and Quinn respond to a shooting at a gas station where 19-year-old Ladeddrick Love was gunned down while his pregnant girlfriend and toddler were both in the car.

On Nov. 10, 2007, Quinn and Vince respond to a 911 call from Evelyn McGuire, who just found her husband, Dennis, shot to death in their backyard.

In Sept. 2004, Vince and Quinn are assigned to a cold case murder from three months before. Ernest Wilson and Lamar Francis were found dead inside a running SUV at an abandoned lumber.

On April 27, 2001, newly minted homicide detectives Quinn and Vince are called to a crime scene in Sylvan Hills; Dexter Freeman is the sole victim of a shooting at a trap house.

On October 6, 2002, Quinn and Vince receive a call about a young Hispanic male found shot to death in an unfinished apartment complex in Dixie Hills.

Vince and Quinn take a trip back to the year 1988 to help a neighboring town's police officer who asks if they will investigate his father's murder. After 28 years, the murder of Leonard Hill remained unsolved and the detectives set out to piece together this decades-old crime. Their investigation leads them to Hill's family where they unearth a shocking revelation.

Vince and Quinn help a new homicide detective who is investigating the brutal murder of an Atlanta woman. Their colleague thinks he has evidence of a confession from a suspect, but the detectives aren't so sure.

Vince and Quinn are assigned to a cold case of a man found shot to death in his car. They try to figure out who wanted the man dead.

Vince and Quinn are assigned to a year-old cold case murder of a man found shot to death in his car; after reviewing the case file again, a piece of original crime scene evidence surfaces, giving detectives a crucial clue to solve this murder.

Vince and Quinn are approached by a colleague for help in a cold case where a young man was found shot to death on a sidewalk; detectives will have to go the extra mile to find the owner of this car and ultimately the killer of this innocent victim.

A young woman is killed in a flashy car riddled with bullets in a quiet Atlanta suburb, and detectives Quinn and Vince can tell this was a shootout with multiple gunmen. However, they must determine whether the victim was really the intended target.

Vince and Quinn are called to a crime scene where a young man is found robbed and shot to death in his pick-up truck. They uncover a string of violence in the neighbourhood and will have to work quickly to find those responsible.

A shooting in a rap studio leaves one man dead and several critically injured; Quinn and Vince take over the cold case and must restart the investigation from the beginning to figure out who is responsible for the murder and robbery scheme.

Officers rush to an apartment complex for a robbery in progress, and they arrive on the scene to find a man who has jumped to his death; Vince and Quinn must determine who is responsible for this terrible outcome and why.

A botched robbery leaves one man dead and his girlfriend traumatized; Quinn and Vince learn that this is a string of increasingly violent crimes across Atlanta and must bring down a gang of emboldened criminals to save more people from similar fates.

While working a homicide at an abandoned home, Quinn and Vince discover a second body hidden inside a closet and the investigation quickly leads them on the hunt for a suspect known as Murder Man.

In a first for the detectives, Quinn and Vince must prove a young male who is found dead was actually killed in Atlanta; a bloodied eyewitness, an active kidnapping and a mystery suspect lead them to uncover a tale of deadly, good fun.

When a carjacking victim succumbs to his injuries a month later, Quinn and Vince must pick up the pieces of a botched robbery investigation; the search for a stolen SUV and a police pursuit lead the detectives to the unlikeliest of suspects.

After the lead detective is reassigned, Quinn and Vince take over a case involving a man found shot to death inside a vehicle; it takes a village to solve the case his rumors spiral into a violent confrontation.

Quinn and Vince are called to assist after a well-known Atlanta civil servant is gunned down outside his home; stakes are high as detectives piece together a timeline and chase down a mystery caller.

A mother's plea leads Quinn and Vince to begin investigating a homicide while the victim is still alive, and they must navigate a long trail of lies and misdirects before finally learning the truth.

A convenience store clerk is shot multiple times just before closing, but the twists and turns that lead to a break in the case aren't nearly as crazy as what happens after the arrest.

When a man is found dead after a violent carjacking, a surviving witness describes two suspects; fingerprints and mistaken identity lead the case in different directions; Quinn and Vince try a new tactic to identify the killer.

While parked in the driveway of a residential home, a man is shot multiple times; to solve this murder, Quinn and Vince need to locate a key witness, solve an East Point cold case, and uncover a plot for revenge.

Quinn and Vince are called to investigate the death of man found in a trap house in a suburban neighborhood; while uncovering nicknames and chasing down leads, Vince finds himself in a dangerous standoff to bring in the killer.

A casual summer morning turns deadly as a man is killed in a drive-by shooting; to solve this case, Quinn and Vince must build trust with the community and key witnesses to discover the leads they need to find the killer's true motive and identity.

Quinn and Vince are on the case when a man is found murdered in his truck in northwest Atlanta; when one eyewitness contradicts another, the detectives will have to sift through fact and fiction to bring this killer to justice.

When a detective in New York calls Atlanta Police about a case, Quinn and Vince take the call; in doing so, the detectives reopen a cold case about a woman found dead in her apartment; to catch this killer, they'll need to take a trip to New York.

A man is shot in broad daylight, and while eyewitnesses know the killer, they don't know his real name; Quinn and Vince will need to get an eyewitness to identify the killer before they can bring him in, but they still may not have the right guy.

Quinn and Vince investigate the death of a man who fell from his third-floor window, and they have a witness to the whole thing; finding the killers may prove difficult, though, especially when one of them has an alibi.

When a U.S. Veteran is found shot in the abdomen just minutes from his home, Quinn and Vince must assist detective Barker solve the murder; as the case begins to stall, though, it may take the whole neighborhood to help bring the killer in.

When Quinn and Vince get handed the cold case of an 11-year-old's murder, they start tracking down old leads to bring new light to the case; as they dig deeper, a former connection to one of the killers may be the lead they need to solve this murder.

Quinn and Vince investigate the death of a man found lying in the leaves with a gunshot wound to his torso, but as they look into it, they learn about a second victim; to find the killer, they'll have to unravel a series of carjackings and stories.

The sexual assault and murder of a 14-year-old girl in southwest Atlanta has been on ice since 1995, but a new lead sends Quinn and Vince hunting for suspects; as the leads once again cool, finding the killer may mean seeking inside help.

Quinn and Vince get a lead on Nacole's case and learn about another cold case from 2005; solving these cases proves to be a test of patience, but as retirement draws near, the detectives begin to wonder if Nacole's case will ever be solved.